RESUMO
The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV-2) and its expansion to a worldwide pandemic resulted in efforts to assess and develop interventions to reduce the disease burden. Despite the introduction of vaccine programmes against SARS-CoV-2, global incidence levels in early 2022 remained high, demonstrating a need for the development of physiologically relevant models, which are essential for the identification of alternative antiviral strategies. The hamster model of SARS-CoV-2 infection has been widely adopted due to similarities with humans in terms of host cell entry mechanism (via ACE2), and aspects of symptomology and virus shedding. We have previously described a natural transmission hamster model that better represents the natural course of infection. In the present study, we have conducted further testing of the model using the first-in-class antiviral Neumifil, which has previously shown promise against SARS-CoV-2 after a direct intranasal challenge. Neumifil is an intranasally delivered carbohydrate-binding module (CBM) which reduces the binding of viruses to their cellular receptor. By targeting the host cell, Neumifil has the potential to provide broad protection against multiple pathogens and variants. This study demonstrates that using a combination of a prophylactic and therapeutic delivery of Neumifil significantly reduces the severity of clinical signs in animals infected via a natural route of transmission and indicates a reduction of viral loads in the upper respiratory tract. Further refinements of the model are required in order to ensure the adequate transmission of the virus. However, our results provide additional data to the evidence base of Neumifil efficacy against respiratory virus infection and demonstrate that the transmission model is a potentially valuable tool for testing antiviral compounds against SARS-CoV-2.
Assuntos
COVID-19 , SARS-CoV-2 , Animais , Cricetinae , Humanos , SARS-CoV-2/metabolismo , Antivirais/farmacologia , Antivirais/uso terapêutico , Antivirais/química , CarboidratosRESUMO
Humanised antibodies targeting Crimean-Congo Haemorrhagic virus (CCHFV) are needed for the development and standardisation of serological assays. These assays are needed to address a shortfall in available tests that meet regulatory diagnostic standards and to aid surveillance activities to extend knowledge on the distribution of CCHFV. To generate a humanised monoclonal antibody against CCHFV, we have compared two methods: the traditional mouse hybridoma approach with subsequent sequencing and humanisation of antibodies versus a non-animal alternative using a human combinatorial antibody library (HuCAL). Our results demonstrated that the mouse hybridoma followed by humanisation protocol gave higher affinity antibodies. Whilst not yet able to demonstrate the generation of equivalent humanised antibodies without the use of animals, sequencing data enables the subsequent production of recombinant antibodies, thus providing a reduction in future animal usage for this application. Ultimately, our report provides information on development of a humanised standardised control, which can form an important positive control component of serological assays against CCHFV.
Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo , Febre Hemorrágica da Crimeia , Humanos , Animais , Camundongos , Febre Hemorrágica da Crimeia/diagnóstico , Febre Hemorrágica da Crimeia/epidemiologia , Hibridomas , Anticorpos Antivirais , Imunoglobulina GRESUMO
Type I interferon receptor knockout mice (strain A129) were assessed as a disease model of hantavirus infection. A range of infection routes (intramuscular, intraperitoneal and intranasal) were assessed using minimally passaged Seoul virus (strain Humber). Dissemination of virus to the spleen, kidney and lung was observed at 5 days after intramuscular and intraperitoneal challenge, which was resolved by day 14. In contrast, intranasal challenge of A129 mice demonstrated virus tropism to the lung, which was maintained to day 14 post-challenge. These data support the use of the A129 mouse model for future infection studies and the in vivo evaluation of interventions.
Assuntos
Modelos Animais de Doenças , Infecções por Hantavirus , Orthohantavírus/fisiologia , Animais , Orthohantavírus/isolamento & purificação , Orthohantavírus/patogenicidade , Infecções por Hantavirus/patologia , Infecções por Hantavirus/virologia , Febre Hemorrágica com Síndrome Renal/patologia , Febre Hemorrágica com Síndrome Renal/virologia , Rim/virologia , Fígado/patologia , Pulmão/patologia , Pulmão/virologia , Masculino , Camundongos , Camundongos Knockout , RNA Viral/análise , RNA Viral/sangue , Receptor de Interferon alfa e beta/genética , Baço/patologia , Baço/virologia , Tropismo ViralRESUMO
Zika virus (ZIKV) is phylogenetically divided into two lineages comprising African (ZIKVAF) and Asian (ZIKVAS) genotypes. In the type-I interferon receptor deficient mouse model, ZIKVAF causes severe disease with all mice meeting humane endpoints with doses as low as 10 plaque-forming units (pfu) whereas a much milder infection is seen after challenge with ZIKVAS, including with doses as high as 106 pfu. Using this mouse model, the elucidation of cytokine, chemokine, growth factor and acute phase protein responses over the course of infection were studied to determine whether these analytes contributed to the stark difference in clinical outcome. Results demonstrated some significant differences, with the ZIKVAF infection being associated with increases in a higher number of biomarkers than ZIKVAS. When low (10 pfu) and high (106 pfu) challenge doses were compared, animals given the lower virus inoculum showed a wider range of responses, indicating a different disease progression compared to those challenged with high doses. These results aid with elucidating the different outcomes with the two lineages of ZIKV and with future work to assess pathogenicity of virus infection.
Assuntos
Proteínas de Fase Aguda/metabolismo , Quimiocinas/sangue , Citocinas/sangue , Peptídeos e Proteínas de Sinalização Intercelular/sangue , Infecção por Zika virus/metabolismo , Zika virus/patogenicidade , Animais , Quimiocinas/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Inflamação/metabolismo , Inflamação/virologia , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Masculino , Camundongos , Receptor de Interferon alfa e beta/deficiência , Receptor de Interferon alfa e beta/genética , Receptor de Interferon alfa e beta/metabolismo , Infecção por Zika virus/fisiopatologia , Infecção por Zika virus/virologiaRESUMO
During February 2018-January 2019, we conducted large-scale surveillance for the presence and prevalence of tick-borne encephalitis virus (TBEV) and louping ill virus (LIV) in sentinel animals and ticks in the United Kingdom. Serum was collected from 1,309 deer culled across England and Scotland. Overall, 4% of samples were ELISA-positive for the TBEV serocomplex. A focus in the Thetford Forest area had the highest proportion (47.7%) of seropositive samples. Ticks collected from culled deer within seropositive regions were tested for viral RNA; 5 of 2,041 ticks tested positive by LIV/TBEV real-time reverse transcription PCR, all from within the Thetford Forest area. From 1 tick, we identified a full-length genomic sequence of TBEV. Thus, using deer as sentinels revealed a potential TBEV focus in the United Kingdom. This detection of TBEV genomic sequence in UK ticks has important public health implications, especially for undiagnosed encephalitis.
Assuntos
Vírus da Encefalite Transmitidos por Carrapatos , Ixodidae/virologia , Animais , Cervos/parasitologia , Vírus da Encefalite Transmitidos por Carrapatos/genética , Encefalite Transmitida por Carrapatos/epidemiologia , Encefalite Transmitida por Carrapatos/transmissão , Ensaio de Imunoadsorção Enzimática , Feminino , Testes de Inibição da Hemaglutinação , Humanos , Masculino , Filogenia , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Espécies Sentinelas/virologia , Análise de Sequência de RNA , Reino Unido/epidemiologiaRESUMO
Ebola virus (EBOV) represents a major concern to global health due to the unpredictable nature of outbreaks. Infection with EBOV can cause a severe viral haemorrhagic fever with no licensed vaccine or treatment, restricting work with live EBOV to Containment/Biosafety Level 4 facilities. Whilst the magnitude of recent outbreaks has provided an impetus for vaccine and antiviral development, establishing the efficacy of candidate vaccine materials relies on EBOV challenge models and advanced human trials should outbreaks occur and where logistics and funding allow. To address these hurdles in vaccine development, we investigated whether a recently established serological reference standard, the 1st WHO International Standard for Ebola virus antibody, could be used to provide a quantifiable correlate of immune protection in vivo. Dilutions of the International Standard were inoculated into naïve guinea pigs 24â¯h before challenge with a lethal dose of Ebola virus. Only subjects receiving the highest dose of the International Standard exhibited evidence of delayed progression. Due to it being a WHO established reagent and available globally upon request, this standard allows for effective comparisons of data between laboratories and may prove valuable to select the candidate vaccines that are most likely to confer humoral immune protection ensuring the most promising candidates progress into efficacy studies.
Assuntos
Formação de Anticorpos/imunologia , Vacinas contra Ebola/administração & dosagem , Ebolavirus/imunologia , Doença pelo Vírus Ebola/prevenção & controle , Animais , Desenvolvimento de Medicamentos , Vacinas contra Ebola/imunologia , Feminino , Cobaias , Doença pelo Vírus Ebola/imunologia , Imunização Passiva/métodosRESUMO
The presence of tick-borne encephalitis virus (TBEV) was detected in a questing tick pool in southern England in September 2019. Hitherto, TBEV had only been detected in a limited area in eastern England. This southern English viral genome sequence is distinct from TBEV-UK, being most similar to TBEV-NL. The new location of TBEV presence highlights that the diagnosis of tick-borne encephalitis should be considered in encephalitic patients in areas of the United Kingdom outside eastern England.
Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Encefalite Transmitida por Carrapatos/diagnóstico , Ixodes/virologia , RNA Viral/genética , Animais , Cervos , Vírus da Encefalite Transmitidos por Carrapatos/genética , Encefalite Transmitida por Carrapatos/epidemiologia , Inglaterra/epidemiologia , Humanos , Filogenia , Estações do Ano , Estudos Soroepidemiológicos , Sequenciamento Completo do GenomaRESUMO
Recent studies have shown that transcriptomic analysis of blood samples taken from patients with acute Ebola virus disease (EVD) during the 2013-2016 West African outbreak was suggestive that a severe inflammatory response took place in acutely ill patients. The significant knowledge gained from studying the Makona variant, a cause of the largest known EVD outbreak, may be applicable to other species of ebolavirus, and other variants of the Ebola virus (EBOV) species. To investigate the ability of Makona to initiate an inflammatory response in human macrophages and characterise the host response in a similar manner to previously characterised EBOV variants, the human monocytic cell line THP-1 was differentiated into macrophage-like cells and infected with Makona. RNA-Seq and quantitative proteomics were used to identify and quantify host mRNA and protein abundance during infection. Data from infection with Reston virus (RESTV) were used as comparators to investigate changes that may be specific to, or enhanced in, Makona infection in relation to a less pathogenic species of ebolavirus.. This study found demonstrable induction of the inflammatory response, and increase in the activation state of THP-1 macrophages infected with Makona. NFκB and inflammation-associated transcripts displayed significant changes in abundance, reflective of what was observed in human patients during the 2013-2016 EBOV outbreak in West Africa, and demonstrated that transcriptomic changes found in Makona-infected cells were similar to that observed in Reston virus infection and that have been described in previous studies of other variants of EBOV.
Assuntos
Ebolavirus/isolamento & purificação , Ebolavirus/patogenicidade , Citocinas/genética , Citocinas/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Doença pelo Vírus Ebola/virologia , Humanos , Interferons/genética , Interferons/metabolismo , Macrófagos/imunologia , Macrófagos/virologia , Proteômica , Células THP-1RESUMO
In the UK, research on hazard group 4 (HG4) pathogens requires specialised Containment Level 4 (CL4) facilities. These differ from Biosafety Level 4 (BSL4) conditions in that work is conducted in class III microbiological safety cabinets for primary containment instead of using positive pressure suits. This presents unique challenges associated with the physical restrictions of working in a limited space, and prohibits the use of many techniques and specialist equipment. In consequence, detailed studies on the biology of HG4 pathogens and in particular their immunological relationships with the host are understudied in the UK; for example, the majority of immunological assays with which the immune system is interrogated require specialist equipment that is unsuitable for CL4. Multiplexing to simultaneously measure multiple analytes is increasingly being used in immunological studies. This assay is attractive for CL4 work because it reduces the time spent in the laboratory whilst maximising the use of valuable sample volume. The Luminex microsphere approach allows for the determination of many cytokines and chemokines, however, the detection system uses fixed aligned lasers and integrated computer systems which are unsuitable for use at CL4. Therefore, we have developed an approach in which the Luminex assay is conducted within the CL4 laboratory and a formalin-fixation stage is introduced to allow for analysis to be undertaken outside of containment. Quality control preparations allow the assay characteristics to be monitored and analysis of assay performance to be evaluated. Our data demonstrate that Luminex is an applicable tool for use at CL4 and that assays can be run reliably to generate reproducible standardised data across different plates and individual experiments.
Assuntos
Contenção de Riscos Biológicos/normas , Ensaios de Triagem em Larga Escala/instrumentação , Laboratórios/normas , Microbiologia/normas , Microesferas , Serviços de Laboratório Clínico , Doenças Transmissíveis/diagnóstico , Doenças Transmissíveis/microbiologia , Fixadores/química , Formaldeído/química , Ensaios de Triagem em Larga Escala/métodos , Ensaios de Triagem em Larga Escala/normas , Humanos , Controle de Qualidade , Reprodutibilidade dos Testes , Fixação de Tecidos/métodos , Fixação de Tecidos/normasRESUMO
The Gn subcomponent of the Gn-Gc assembly that envelopes the human and animal pathogen, Rift Valley fever virus (RVFV), is a primary target of the neutralizing antibody response. To better understand the molecular basis for immune recognition, we raised a class of neutralizing monoclonal antibodies (nAbs) against RVFV Gn, which exhibited protective efficacy in a mouse infection model. Structural characterization revealed that these nAbs were directed to the membrane-distal domain of RVFV Gn and likely prevented virus entry into a host cell by blocking fusogenic rearrangements of the Gn-Gc lattice. Genome sequence analysis confirmed that this region of the RVFV Gn-Gc assembly was under selective pressure and constituted a site of vulnerability on the virion surface. These data provide a blueprint for the rational design of immunotherapeutics and vaccines capable of preventing RVFV infection and a model for understanding Ab-mediated neutralization of bunyaviruses more generally.
Assuntos
Anticorpos Monoclonais/farmacologia , Anticorpos Antivirais/farmacologia , Vírus da Febre do Vale do Rift/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Neutralizantes/farmacologia , Chlorocebus aethiops , Feminino , Glicoproteínas/química , Glicoproteínas/metabolismo , Células HEK293 , Humanos , Imunização , Imunoglobulina G/metabolismo , Camundongos Endogâmicos BALB C , Modelos Biológicos , Testes de Neutralização , Domínios Proteicos , Coelhos , Proteínas Recombinantes/farmacologia , Vírus da Febre do Vale do Rift/efeitos dos fármacos , Células Vero , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/metabolismoRESUMO
Crimean-Congo hemorrhagic fever virus is a risk group 4 pathogen, which mandates the use of maximum containment facilities, often termed biosafety level 4 or containment level 4 when working with infectious materials. Diagnostic and research work involving live viruses in such laboratories is time-consuming and inconvenient, resulting in delays. Herein, we show that serum neutralizing activity against the virus can be measured in low-containment laboratories using a pseudotyped virus.
Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo , Febre Hemorrágica da Crimeia/diagnóstico , Testes de Neutralização/métodos , Vesiculovirus , Virologia/métodos , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Linhagem Celular , Chlorocebus aethiops , Vírus da Febre Hemorrágica da Crimeia-Congo/química , Vírus da Febre Hemorrágica da Crimeia-Congo/genética , Vírus da Febre Hemorrágica da Crimeia-Congo/imunologia , Humanos , Células Vero , Vesiculovirus/genética , Vesiculovirus/fisiologiaRESUMO
Zika virus (ZIKV) falls into two lineages: African (ZIKVAF) and Asian (ZIKVAS). These lineages have not been tested comprehensively in parallel for disease progression using an animal model system. Here, using the established type-I interferon receptor knockout (A129) mouse model, it is first demonstrated that ZIKVAF causes lethal infection, with different kinetics of disease manifestations according to the challenge dose. Animals challenged with a low dose of 10 plaque-forming units (pfu) developed more neurological symptoms than those challenged with 5-log higher doses. By contrast, animals challenged with ZIKVAS displayed no clinical signs or mortality, even at doses of 106 pfu. However, viral RNA was detected in the tissues of animals infected with ZIKV strains from both lineages and similar histological changes were observed. The present study highlights strain specific virulence differences between the African and Asian lineages in a ZIKV mouse model.
Assuntos
Receptor de Interferon alfa e beta/deficiência , Infecção por Zika virus/patologia , Zika virus/patogenicidade , Estruturas Animais/patologia , Estruturas Animais/virologia , Animais , Modelos Animais de Doenças , Progressão da Doença , Histocitoquímica , Masculino , Camundongos Knockout , RNA Viral/análise , Análise de Sobrevida , Virulência , Zika virus/classificaçãoRESUMO
Crimean-Congo haemorrhagic fever virus (CCHFV) is a deadly human pathogen of the utmost seriousness being highly lethal causing devastating disease symptoms that result in intense and prolonged suffering to those infected. During the past 40years, this virus has repeatedly caused sporadic outbreaks responsible for relatively low numbers of human casualties, but with an alarming fatality rate of up to 80% in clinically infected patients. CCHFV is transmitted to humans by Hyalomma ticks and contact with the blood of viremic livestock, additionally cases of human-to-human transmission are not uncommon in nosocomial settings. The incidence of CCHF closely matches the geographical range of permissive ticks, which are widespread throughout Africa, Asia, the Middle East and Europe. As such, CCHFV is the most widespread tick-borne virus on earth. It is a concern that recent data shows the geographic distribution of Hyalomma ticks is expanding. Migratory birds are also disseminating Hyalomma ticks into more northerly parts of Europe thus potentially exposing naïve human populations to CCHFV. The virus has been imported into the UK on two occasions in the last five years with the first fatal case being confirmed in 2012. A licensed vaccine to CCHF is not available. In this review, we discuss the background and complications surrounding this limitation and examine the current status and recent advances in the development of vaccines against CCHFV.
Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo/imunologia , Febre Hemorrágica da Crimeia/imunologia , Febre Hemorrágica da Crimeia/prevenção & controle , Vacinas/imunologia , Animais , Infecção Hospitalar/imunologia , Infecção Hospitalar/prevenção & controle , Geografia/métodos , Humanos , Incidência , Ixodidae/imunologiaRESUMO
Despite sporadic outbreaks of Ebola virus (EBOV) over the last 4 decades and the recent public health emergency in West Africa, there are still no approved vaccines or therapeutics for the treatment of acute EBOV disease (EVD). In response to the 2014 outbreak, an ovine immunoglobulin therapy was developed, termed EBOTAb. After promising results in the guinea pig model of EBOV infection, EBOTAb was tested in the cynomolgus macaque non-human primate model of lethal EBOV infection. To ensure stringent therapeutic testing conditions to replicate likely clinical usage, EBOTAb was first delivered 1, 2 or 3 days post-challenge with a lethal dose of EBOV. Results showed a protective effect of EBOTAb given post-exposurally, with survival rates decreasing with increasing time after challenge. Viremia results demonstrated that EBOTAb resulted in a decreased circulation of EBOV in the bloodstream. Additionally, assay of liver enzymes and histology analysis of local tissues identified differences between EBOTAb-treated and untreated groups. The results presented demonstrate that EBOTAb conferred protection against EBOV when given post-exposure and should be explored and developed further as a potential intervention strategy for future outbreaks, which are likely to occur.
Assuntos
Anticorpos Antivirais/farmacologia , Ebolavirus/imunologia , Doença pelo Vírus Ebola/tratamento farmacológico , Doença pelo Vírus Ebola/imunologia , Imunoglobulina G/farmacologia , Animais , Biomarcadores , Modelos Animais de Doenças , Ebolavirus/genética , Doença pelo Vírus Ebola/mortalidade , Doença pelo Vírus Ebola/virologia , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Fígado/metabolismo , Fígado/patologia , Fígado/virologia , Macaca fascicularis , Masculino , Profilaxia Pós-Exposição , Primatas , RNA Viral , Fatores de Tempo , Resultado do Tratamento , Carga ViralRESUMO
Crimean-Congo hemorrhagic fever virus (CCHFV) is a major cause of tick-borne viral hemorrhagic disease in the world. Despite of its importance as a deadly pathogen, there is currently no licensed vaccine against CCHF disease. The attachment glycoprotein of CCHFV (Gn) is a potentially important target for protective antiviral immune responses. To characterize the expression of recombinant CCHFV Gn in an insect-cell-based system, we developed a gene expression system expressing the full-length coding sequence under a polyhedron promoter in Sf9 cells using recombinant baculovirus. Recombinant Gn was purified by affinity chromatography, and the immunoreactivity of the protein was evaluated using sera from patients with confirmed CCHF infection. Codon-optimized Gn was successfully expressed, and the product had the expected molecular weight for CCHFV Gn glycoprotein of 37 kDa. In time course studies, the optimum expression of Gn occurred between 36 and 48 hours postinfection. The immunoreactivity of the recombinant protein in Western blot assay against human sera was positive and was similar to the results obtained with the anti-V5 tag antibody. Additionally, mice were subjected to subcutaneous injection with recombinant Gn, and the cellular and humoral immune response was monitored. The results showed that recombinant Gn protein was highly immunogenic and could elicit high titers of antigen-specific antibodies. Induction of the inflammatory cytokine interferon-gamma and the regulatory cytokine IL-10 was also detected. In conclusion, a recombinant baculovirus harboring CCHFV Gn was constructed and expressed in Sf9 host cells for the first time, and it was demonstrated that this approach is a suitable expression system for producing immunogenic CCHFV Gn protein without any biosafety concerns.
Assuntos
Regulação Viral da Expressão Gênica/fisiologia , Vírus da Febre Hemorrágica da Crimeia-Congo/metabolismo , Proteínas Virais/metabolismo , Animais , Baculoviridae/genética , Sequência de Bases , Códon , Citocinas/metabolismo , Feminino , Vírus da Febre Hemorrágica da Crimeia-Congo/genética , Camundongos , Camundongos Endogâmicos BALB C , Células Sf9 , Baço/metabolismo , Proteínas Virais/genéticaRESUMO
The Ebola virus (EBOV) variant Makona (which emerged in 2013) was the causative agent of the largest outbreak of Ebola Virus Disease recorded. Differences in virus-host interactions between viral variants have potential consequences for transmission, disease severity and mortality. A detailed profile of the cellular changes induced by the Makona variant compared with other Ebola virus variants was lacking. In this study, A549 cells, a human cell line with a robust innate response, were infected with the Makona variant or with the Ecran variant originating from the 1976 outbreak in Central Africa. The abundance of viral and cellular mRNA transcripts was profiled using RNASeq and differential gene expression analysis performed. Differences in effects of each virus on the expression of interferon-stimulated genes were also investigated in A549 NPro cells where the type 1 interferon response had been attenuated. Cellular transcriptomic changes were compared with those induced by human respiratory syncytial virus (HRSV), a virus with a similar genome organisation and replication strategy to EBOV. Pathway and gene ontology analysis revealed differential expression of functionally important genes; including genes involved in the inflammatory response, cell proliferation, leukocyte extravasation and cholesterol biosynthesis. Whilst there was overlap with HRSV, there was unique commonality to the EBOV variants.
Assuntos
Ebolavirus/crescimento & desenvolvimento , Interações Hospedeiro-Patógeno , Transcriptoma , Células A549 , Perfilação da Expressão Gênica , Humanos , Vírus Sincicial Respiratório Humano/crescimento & desenvolvimento , Análise de Sequência de RNARESUMO
BACKGROUND: Despite several studies on the seroprevalence of antibodies against Crimean-Congo Haemorrhagic Fever virus (CCHFV) from humans and cattle in Nigeria, detailed investigation looking at IgG and IgM have not been reported. Additionally, there have been no confirmed cases of human CCHFV infection reported from Nigeria. PRINCIPAL FINDINGS: Samples from sera (n = 1189) collected from four Local Government Areas in Borno State (Askira/Uba, Damboa, Jere and Maiduguri) were assessed for the presence of IgG and IgM antibodies. The positivity rates for IgG and IgM were 10.6% and 3.5%, respectively. Additionally, sera from undiagnosed febrile patients (n = 380) were assessed by RT-PCR assay for the presence of CCHFV RNA. One positive sample was characterised by further by next generation sequencing (NGS) resulting in complete S, M and L segment sequences. CONCLUSIONS: This article provides evidence for the continued exposure of the human population of Nigeria to CCHFV. The genomic analysis provides the first published evidence of a human case of CCHFV in Nigeria and its phylogenetic context.
Assuntos
Anticorpos Antivirais/sangue , Vírus da Febre Hemorrágica da Crimeia-Congo/isolamento & purificação , Febre Hemorrágica da Crimeia/virologia , Animais , Bovinos , Vírus da Febre Hemorrágica da Crimeia-Congo/classificação , Vírus da Febre Hemorrágica da Crimeia-Congo/genética , Vírus da Febre Hemorrágica da Crimeia-Congo/imunologia , Febre Hemorrágica da Crimeia/sangue , Febre Hemorrágica da Crimeia/epidemiologia , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Nigéria/epidemiologia , Filogenia , Estudos SoroepidemiológicosRESUMO
In light of the recent outbreak of Ebola virus (EBOV) disease in West Africa, there have been renewed efforts to search for effective antiviral countermeasures. A range of compounds currently available with broad antimicrobial activity have been tested for activity against EBOV. Using live EBOV, eighteen candidate compounds were screened for antiviral activity in vitro. The compounds were selected on a rational basis because their mechanisms of action suggested that they had the potential to disrupt EBOV entry, replication or exit from cells or because they had displayed some antiviral activity against EBOV in previous tests. Nine compounds caused no reduction in viral replication despite cells remaining healthy, so they were excluded from further analysis (zidovudine; didanosine; stavudine; abacavir sulphate; entecavir; JB1a; Aimspro; celgosivir; and castanospermine). A second screen of the remaining compounds and the feasibility of appropriateness for in vivo testing removed six further compounds (ouabain; omeprazole; esomeprazole; Gleevec; D-LANA-14; and Tasigna). The three most promising compounds (17-DMAG; BGB324; and NCK-8) were further screened for in vivo activity in the guinea pig model of EBOV disease. Two of the compounds, BGB324 and NCK-8, showed some effect against lethal infection in vivo at the concentrations tested, which warrants further investigation. Further, these data add to the body of knowledge on the antiviral activities of multiple compounds against EBOV and indicate that the scientific community should invest more effort into the development of novel and specific antiviral compounds to treat Ebola virus disease.
Assuntos
Antivirais/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Ebolavirus/efeitos dos fármacos , Animais , Antivirais/administração & dosagem , Linhagem Celular , Modelos Animais de Doenças , Cobaias , Doença pelo Vírus Ebola/tratamento farmacológico , Humanos , Resultado do TratamentoRESUMO
The antiviral properties of iminosugars have been reported previously in vitro and in small animal models against Ebola virus (EBOV); however, their effects have not been tested in larger animal models such as guinea pigs. We tested the iminosugars N-butyl-deoxynojirimycin (NB-DNJ) and N-(9-methoxynonyl)-1deoxynojirimycin (MON-DNJ) for safety in uninfected animals, and for antiviral efficacy in animals infected with a lethal dose of guinea pig adapted EBOV. 1850 mg/kg/day NB-DNJ and 120 mg/kg/day MON-DNJ administered intravenously, three times daily, caused no adverse effects and were well tolerated. A pilot study treating infected animals three times within an 8 hour period was promising with 1 of 4 infected NB-DNJ treated animals surviving and the remaining three showing improved clinical signs. MON-DNJ showed no protective effects when EBOV-infected guinea pigs were treated. On histopathological examination, animals treated with NB-DNJ had reduced lesion severity in liver and spleen. However, a second study, in which NB-DNJ was administered at equally-spaced 8 hour intervals, could not confirm drug-associated benefits. Neither was any antiviral effect of iminosugars detected in an EBOV glycoprotein pseudotyped virus assay. Overall, this study provides evidence that NB-DNJ and MON-DNJ do not protect guinea pigs from a lethal EBOV-infection at the dose levels and regimens tested. However, the one surviving animal and signs of improvements in three animals of the NB-DNJ treated cohort could indicate that NB-DNJ at these levels may have a marginal beneficial effect. Future work could be focused on the development of more potent iminosugars.
Assuntos
1-Desoxinojirimicina/análogos & derivados , 1-Desoxinojirimicina/farmacologia , Ebolavirus , Doença pelo Vírus Ebola/tratamento farmacológico , Animais , Modelos Animais de Doenças , Cobaias , Projetos PilotoRESUMO
Zika virus (ZIKV) is an emerging pathogenic flavivirus currently circulating in numerous countries in South America, the Caribbean, and the Western Pacific Region. Using an unbiased metagenomic sequencing approach, we report here the first complete genome sequence of ZIKV isolated from a clinical semen sample.